From cats dressed up for Halloween, to obese dogs overfed by doting owners, it can seem as though the UK is not just a national of animal lovers, but animal fanatics. But with the financial crises squeezing people from their homes and slashing family budgets, our pets are feeling the full bite of the recession.

Animal sanctuaries say they are full to bursting as formerly beloved pets from cats to chameleons are handed over by owners who can no longer afford them. Cases of neglect are also on the rise, according to the charities, some of which have had to stop taking on healthy animals because of the pressure of emergency cases. An increasing number of owners are taking the extreme measures of abandoning their animals at the vet, in repossessed homes and even on the streets, just to be rid of them.

The Dogs Trust says the number of stray or abandoned dogs has reached an 11-year high in 2011, and that 20 dogs a day are being put down by local authorities across the country. On top of this, the charity has seen a 56% increase in the number of people giving it their dogs because of housing problems – while the Blue Cross animal charity says it has had 50% more stray and abandoned pets this year, compared with the same period last year.

Frustrated when full-up sanctuaries can't accommodate their unwanted pets, some owners are taking matters into their own hands, says Sarah Bussell, centre manager at the Blue Cross adoption centre in Tiverton, Devon. "We have had people throwing their cats over the gate because they are so desperate."

Families who have to move into rented accommodation because of financial problems find they can't take their pets with them and are being forced to give them up, she says. Other animal sanctuaries say they have also noticed a marked drop in people willing to rehome animals because of a lack of space and money – all while the charities themselves are seeing donations drop. This has become such a problem that the Dogs Trust has begun a campaign to encourage letting agents and landlords to be more pet friendly at a time when more people are renting on a permament basis.

Workers putting in longer hours during the downturn is also having an effect, with dogs given away because they become destructive and noisy when left alone for extended periods, says Bussell. Meanwhile, the cost of vets' bills is not just putting pressure on owners but preventing people from neutering their animals. "That can be expensive, so we are getting more puppies and kittens," she says. "The recession is still having an effect and we have probably not seen the worst of it," she says.

Lindsey Quinlan, operations manager at Battersea Dogs & Cats Home, says the number of calls the home has had from people wishing to give up their pet has rocketed over the past year. She adds that housing issues are among the reasons most often cited by people handing over their pets, but there are other problems. "We are also seeing an increasing number of animals coming into our care who are the victims of cheap and unregulated website sales. Often these animals are poorly socialised and suffering from medical conditions."

Horse welfare charities say they have been shocked at the change and that unprecedented numbers of horses and ponies are being abandoned. Redwings, the largest horse sanctuary in the UK, says the number of straying or abandoned horses reported to it jumped from 160 in 2009 to 241 in 2010. So far this year it has had 157 reported, despite the fact that its busiest period has not yet begun.

Amy Williams from HorseWorld says the cases of neglect seen in the last year have been horrific. "We had one in February of a wilfully neglected horse that was only four months old, but had collapsed. A grave had been dug next to him so when he finally died they could just push him in. They weren't even hoping someone would find him – they were actually waiting for him to die.

"We have also had quite a few requests from people to take their horses, but we haven't been able to take on healthy animals because we have had to prioritise our spaces for the welfare cases." Owners who found the £4,000 cost of keeping a riding horse each year too high were struggling to find anyone else who could afford it. "People can't give horses away at the moment," she says.

Nicola Markwell says the low price of horses at market is adding to the crisis. "The lowest we have heard of is £2.50. We have heard of people buying 'job lots' and abandoning the ones they don't want." This year's bad harvest means hay and straw are expensive, and people are buying lower quality feed and not maintaining the fences that would keep them safe – which could lead to an increase in vets' bills, according to Williams. "We have had quite a few severely emaciated horses, and also a couple who have been obese – the owners could not afford to keep them in the traditional way so they turned them out with the cows." Both charities say they are regularly giving advice to callers on how to care for their horses more cheaply.

Landlords have been finding themselves at the sharp end of the problem too, according to Iain Newby, who rescues exotic animals at the Dangerous Wild Animal Rescue Facility. He has had to deal with double the number of animals as last year – including turtles, tarantulas and snakes.

"People are unable to pay their rent, doing a moonlight flit and leaving their pets behind," says Newby. "A month ago it was tarantulas left in a tank in a kitchen. We found a gecko without food or water for three weeks abandoned in a rental house in an understairs cupboard."

He says the cost of heating tanks with the current soaring electricity bills, as well as the higher cost of vets' bills for exotic animals, all have an impact in the recession. People who downsize are also facing problems, he says, and coming up with the worst solution – to abandon dangerous and vulnerable animals. "We had a Burmese python abandoned in a house that was being repossessed – it was 8ft long and will get to 20ft. I had to go in and get it out."